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Patented Aug. v21, 1945 "'STATES assert; f;

Mmmm-1ct DYESTUFF INTERMEpIATES i `JohnDavidKemlall., Ilf01'l,"England, aSSignlQr i9 yIlford yLimited, Ilford, England, agritish company y No Drawing. `Application11pni 1g, 195,13, sensi NpQ i 482,494. InGreatBrnainpnlwgs, 1942 n t p i n "18 claims. (Grasa-3021) i- Thisnvention relatesftcthe productionof dye-wf `Where *X and jYeach represent -an .oxygen -atom Lor-a Isulphureagtom, R1 is` a. hydrogen atom or a irre` :zwemmen pf the clifelsiiff` intermediates Maeszordinso thepresentinventon occurs accordhydrocarbon group and R2 and" R3 are Ihydrocar- *bon groups.

Accordingto `this invention dyestuff lintermedi- Mates i'ftheabove `general *Formula1-are produced `(Where R4 is a h'ydrocarhon .group and'thezother above) 'with a. mercaptan` .or a "trithio-orthoformic ester to produce a dyestuff intermediate 4iofnthetypewvhere3X:is;a;sulphur atom, or with an `ortho formicfester to-produce adyestui :intervthe reactionabeing effected, in -,the presence of la.

Vmineral acdior 1an alkylgorxaralkyl saltof afminthe presence of a solvent "and an alkaline con-` 30 symbols have .the meanings assigned to themwv Y ortho formc ester .-10.. grams or higher alkyl groups, aralkyl groups, e. g. benzyl and naphthyl-methyl groups, aryl groups, e. g. phenyl and naphthyl groups, and unsaturated hydrocarbon groups, e. g. allyl and cinnamyl groups. Preferably the groups Ra and R4 are lower alkyl groups. `lquivalentgroups, however, include. the above hydrocarboIl/fgr-ups which are substituted and contain in place of hydrogen atoms substituent groups, e. g. hydroxyl, alkogiy, i amino, substituted amino, alkyl and substituted alkyl groups, or halogen atoms.

As indicated above, the reaction to produce, dyestuff intermediates according tothi'sfinven`v tion is effected in the presence of'a mineral acid or an alkyl or aralkyl salt of a mineral acid, and

in the presence of a solvent. suitable minerall'j acid is hydrochloric acid and, ofthe salts, the

@solution thisyielding the product as light brown alkyl halides are of particular valualnfsomew cases where a mercaptan is used, the mercaptan itself acts as a solvent for the reactants and in such cases no auxiliary solvent is necessary. In other cases a suitable solvent is methyl alcohol.

It is a curious fact, andhas been checked by analysis,that even when the process of the ini vention is effected inthe presence of an alkyl or aralkyl ,salt of. a mineral acid, the product obtained is not a quaternary salt.

separated by filtration and washed. with methyl alcohol. It was found to have a melting point of 116 C.

(c) Alternative preparation of the same dyestuj intermediate acid, 9 ccs. fof ethyl mercaptan and '20^ ccs. of `methyl alcohol were placed in a flask fitted with an inlet tube and a water condenser. The flask was placed in a freezing mixture and hydrochloric acid gas was passed in for 30 minutes.

'y Thereaction mixture was then allowed to stand 'for 24hours and'during this time an oily solid was precipitated; The liquid was decanted and .,thesolidwas recrystallised from ethyl alcohol crystals melting at 116 C. as before. A further quanti-ty of the intermediate can be obtained by `evaporating theA decanted Vliquors Vin` a desiccator f. and recrystallisingtfror'n ethyl;alcoholzsolution) the 'solid which separates.; z

It will be observed from general FormulaII i given above thatthe initial 'compound contains" groups R3 'and' RA which', though they may be different, are really lequivalent'groups.` Forthe 4 `sake of simplicity,"i`n the formulae given above it has been assumed jtha'tthe group R3. remains in the final dyestuif intermediate while the group" R4 is splitoif. .In-actual' practice it is found that if these groups are different it is usually the group of greater molecular weight which remains in the Idyestuff intermediate, the lighter group being removed? Thus in the formulae f considered as interchangeable. A.

The following examples illustrateY the,` inven'- given above, the groups Ra andV R4 gareV to be tion but are not to be regarded as limiting it inA any Way: l f

EXAMPLEl PREPARATION 0F 'rr-ir: 2-"IH1o-3-#ETHYL-4-KETo-5- (fy-ETHYLTHIO CROTONYLIDENE) TETRAHYDRO- THIAzoLE of 5- (w-diacetyl-vinyl) -N -ethyl- (a) Preparation rhodanicacid 20 grams of N-ethyl rhodanic acid and 23 grams of ethoxymethylene-acetyl-acetone Werddissolved in 62 ccs. of lethyl alcohol. 12.21 gms. of fused sodium vacetate were then added and the Whole reuxed for 20 minutes during which time the solution turned dark red. The solution was then cooled and diluted with water to a bulky.

f fand 'W'asfilteredroff` and'recrystallised from" ethyl of 50G-"100 ccs. The solid matter which separated out was then filtered off and Washed with water until free from the red colouration. The product was thus obtained as a light brown solid which on dryingand recrystallisation from ethylalcohol solution was found to'have a melting point of 105 C.

(b') Preparation of .the dyestu, intermediate of methyl iodide and 40y ccsmofzmethyll alcohol were placed in a sealed flask and allowed to stand.

n.After 5' to 'hoursxthe solidswere all linsolution l and after three da'ys standing, the desiredv dyef stuff. intermediate beganto beldepo'sited.v kIt was Bigarfaae'rrorr :orf Nanni/muraria 2 TH1o-3-MErHYL-4-KETo-5 (fy-ETHYLTHIo-CRO- roNYLIDE-NE) eTErRAnYnRo-THIAZOLE (a) Preparation` ofE-(LuQ-dtacetyl-vinyl) -N- l methyl-rhodanic acid This compound was prepared as in Example la` using 18` gms. of N-methyl rhodanic acid instead ofthe-20 grams` N-eth-ylrhodanic acid. The lproductv was obtainedas a light brown solid melting-at12fl C. 1 Instead of using fused sodium acetate there `may be employed 1.2,ccsfof diethylam'ine. ;-IIow .evlzin this case t'isgdesirable. to. .acidity vthe dito decompose any diethylamine salt which may have formed.

(b) Preparation of the di/ectul intermediate J y 8.2 gms.l of 5-(u-diacetyl-vinyl)-N-methylrhodanic acid, 3.6f'c'cs`. vof methyl iodide, 1.4.5- ccs.

of ethyl mercaptan and 20 .cos. of methyl alcohol were reactedtogether in a sealed flask as in Example lb. The reaction proceeded similarly and the product was obtained as a.yellow crystalline yfrhodanic acid, 3.6;ccs. of` trithio ethyl orthoformate, 1.24.ccs.of'methyl iodide and Zuccs. of

. methyl alcohol. were .mixed together-in a. ysmall flask. and allowed to Ystand fororle1day`."` yThe flask wasthen heated for tenk minutes ona'lwater alcohol: It'fwas Vfound 'tovhave, `as -iingi-pointof `134:" C.

(a) Preparation of 5 (w diacetyZ- viLtyD N- methylk-oarhoddm'c acid 1.31 gms. of N-methyl oka'rhodanic "acid, 2.0-

gms. of ethoxy-methylene-acetyl-acetone and 5 ccs. of ethyl alcohol were warmed together to form a solution and 1.39 ccs. of triethylamine 'was '.added. ..The solution was heatedn for 30 :min-

l-.ute'siduring which timeit'turned fred. {The soluttion was th'endiluteduto .40 ccs. `with-water, cooled, =acdied with :8 cc. of lglacial aceticaci'dyand -the'reddish vsolid `which `precipitated Iwas ltered off. On recrystallisation `of this solid from Vethyl alcohol .solution the .desired compound was `obitained as a lightbrown solid melting :at 152 C. l(b)A Preparation `ofthe dyestuz intermediate 3.5 gms. of -(w-diacetyl-vinyl) -N-methyl-oxa- .rhodanicfacid, 6.4 .ccsaof ethyl fmercaptan,` 1.8 Accs. of methyl.iodide-.and` ccs. yof. methyl 1alco` hol were placed in a sealed` fla-skand allowedto stand for 3 days. The reaction mixture was then reuxed on a water bath for 3 hours and then allowed to cool. `The desired `dyestuif intermediate crystallised out and after separation and `boiling out with ccs; of `ethyl alcohol it was obtained as yellow needles melting at 178 C.

EXAMPLE '4` oscarhodan'ic acid gms. of N-ethyioxarhodanicacid, 1o "gms, of` thoxy#-methylene-acetylacetone 25 ccs. of

*ethyl alcohol# cos. `of' triethylamine and 4 ccs.

of acetic `acid were usediand the preparation t effected as in Example 3a. "Theproduc't *was (b) Preparation of thefd'yestugb intermediate obtained "as `light brown crystals, melting at' 3 gms. ci" t5-(w-diacetyl-vinyl) -N-ethyl-oxa-- rhodanic acid, 5.2 ccs. of `ethyl mercaptan, 1.46 ccs. of methyl iodide and ,20 ccs. of methyl alcohol were mixed '.together, reiluxed forV 1 hour, allowed to stand for'24hours andthenere'uxed for a` further 3 hours. After furtherjstanding the solid material which precipitated was fltered off and M5 -boiled out with ethyl alcohol, yieldingtheprod- F215 .grams of 5-(wvdiacetyl-Vinyl) -N-methyllrhodanic acid, (prepared as in Example 2a), 5.5 ccs. of ethyl-ortho-formate, 9 ccs.:.of :absolute ethyl lalcohol and .a drop of concentrated sul- .phuric .acid f were .mixed .together and allowed to stand for 3 days. The desired dyestuff `intermediate which precipitated fromsolution was liltered off and recrystallised from methyl alcohoL It was obtained.` as matted yellow needles, melting at 149 C.

PREPARATION or ZJIHIOTS-IETHYIQA-KETo-B-(fy- ETHoXY-,CROTONYLIDENm :TETRAHYDRO THIA- zoLE (a). 5 c gms; Hof` xftw-'diacetyl-vinyl) N-ethyl- .11.4 zccs.' of .absolute ethyl alcohol. and `1a i drop of concentnated sulphuric acid twas `reacted `.together iastiniExamplez. The `dyestufl intermediate was thusxbtained as alight yellow 1 crystalline .r solid --meltngaatl27C;. t.

-(b,) ...Alternative `gmieparationJofJ .the rsame dyestuj l `allowed 'to .stand `for 'I days 4with 'intermittent .Warming .to dissolyethe reactants. The solid `present was thenltered `oif,.washed with ethyl alcohol and purified by boiling out with .theethyl alcohol. TheI product consisted' of 4matted yellow needles, M. P. 1165 C. i i

(a) Preparation .of` 5 (w-diacetyvZ-vinyl) -rhodam'c racid 1 5.32 gms. of rhodanicjacid-BJO fgms. of ethoxy methylene acetyl acetonel and 20 ccs. of ethyl alcohol were heated under a redux condenser and 5.6 ccs. triethylamine was added.` The mixture :was yheate-dfiorBilliriinutes, 'after which time thersolution was `a deepfred-orange colour. `The solution was cooled, :diluted and; acidifred iwith 2.4 ccs. acetic acid,4 and the solid removed by ltration, washed with water and therr with a little ethyl alcohol. After recrystallisation from ethyl alcohol, the product was obtained `as a light' brown solidyM. 200IC. -wit-h decomposition. (b) Preparation of the dyestaintermediate 2.43 gms..v of `5-(w-aiacetyl-vimfi -rhodanic acid, 4.4 ;ccs. of' ethyl mercaptan, 1.24 ccs.. of

methyl iodide and 20 ccs. ofmethyl alcohol were mixedtogether andallowedto stand in a sealed 'flask for 3l-4 days when the solid went `into-solu- `t'ionwarrd crystals of `a'new solid were formed. VThis `was` 'removed by filtration, washed with methyl` alcohol '-an'dl then recrystallised from methyl alcohol. "Pheproduct thus-obtained was A'a light brown solidwhichemeltedat 154 C.

IEXAMPLEle` PREPARATION or l Z-'THIo-l-KETo-B-(fy-ErHoxY JCRoToNYLIDENE) -TETRAHYDRofTHTAzoLE 2.43 gms. 5-(t1-ditte@w1-vinyl frhodarmfk acid.

prepared astinExample 8a,"3.*73" ccs'. of ethyl ortho formate,` 6.1 ccs. of ethyl .alcohol and l drop of concentrated sulphurc acdfwere reacted to gether as in Example "7. The product was o'btained as asdark yellow solid, M. P. 213 C.

EXAMPLE 10 t PREPARATION 0F THE DYESTUFF INTERMEDIATE 2- (a) Preparation of 5-mdipfopionymmyo. N- methyl-rhodam'c acid l .13.0 egms. of .N-fmethyl lrhodanic 1 acid, .5;O.lgms.

'.755 rof .ethoxyemethylenedipropohyl ..methane;:and

(b) Preparation of the dyestu intermediate 2.3 gms. of 5-(w-dipropionyl-Vinyl)-N-methylrhodanic acid, 4,0 ccs. ofethyl mercaptan, 1 cc. "1 of methyl iodide and l5 ccs. .of Ymethyl alcohol were allowed to stand for 48 hours and the prod-uct separated asin Example 8b. The product was obtained. after recrystallisation from` methyl alcohol as brown Icrystals, with a blueI reflex, M. P. 121C.

The dyestuff intermediates `of .this invention are of considerable value inthe production of dyestuls capable of optically sensitising silver 4 halide photographic emulsions. It is found that not only is the SR2 or -ORz group reactive but also the :S group in the rhodanine nucleus is reactive, which'is` contrary to allprevious eX perience with such =S groups. Processes `forI the manufacture of dyestufs using the intermediates of the present invention are described in copending application No. 482,493 led on even date herewith. i

What I claim is: l*

1. Process for the production of dyestui intermediates which comprises condensing a compound of the general formula:

(where Y represents an atom selected from the class consisting of oxygen atoms and sulp-hur atoms, R1 is selected from the vclass consisting of the hydrogen atom and hydrocarbon groups and R3 and R4. are each hydroc-arbon groups) with a compound selected from the class consisting of compounds of the formula RzSI-I, (R2S) aCI-I and (RzO)3CH Where R2 is a hydro` carbon group, in the presence of a condensing agent selected from the class consisting of mineral acids and alkyl andaralkyl salts of mineral acids and in the presence of a solvent for the reactants.

2. Process for the production of dyestufi intermediates which comprises condensing a compound of the general formula: l

y (where Y represents an atom selected from the class consisting of oxygen atoms and sulphur atoms, R1 is selected from the class consisting of the hydrogen atom and hydrocarbon groups and R3 and R4 are each lower alkyl groups) with a lower alkyl mercaptan in the presence `of a condensing agent selected from the class consisting of hydrochloric acid and alkyl and aralkyl chlorides and in the` presence of a solvent for the reactants.

,3. Process according tov claim 2 wherein the mercaptan itself serves as the solvent for the reactants. Y

54.Process for the production of dyestuf inter-- mediates which comprises condensing a compound of the general formula:

(where Y represents an atom selected from the class consisting of oxygen atoms and sulphur atoms, R1 is selected from the class consisting of the hydrogen atomand hydrocarbon groups and R3 and R4 are each lower' alkyl groups) with .ar trithio ortho-formic lower-alkyl ester in the presence of a condensing agent selected from the class consisting of hydrochloric acid and alkyl and aralkyl chlorides and in the presence of a solvent for the reactants.

5. Process for the production of dyestufl intermediates which comprises condensing a compound of the general formula:

(where Y represents'an atom selected from the class consisting of oxygen atoms and sulphur atoms, R1 is selected from the class consisting of the hydrogen atom and hydrocarbon groups and R3 and R4 are each lower alkyl groups) with an ortho-formic lower-alkyl ester in the presence of a condensing agent selected from the class consisting of hydrochloric acid and alkyl and aralkyl chlorides and in the presence of a solvent for the reactants.

6. Process for the production of dyestu intermediates which comprises condensing a compound of the general formula:

(Where .Y represents a sulphur atom and R1, R3 .and R4 are each lower alkyl groups) with a lower alkyl mercaptan in the presence of a condensing agent selected from the class consisting of `hydro- .chloric acid and alkyl and aralkyl chlorides and in the presence of a solvent for the reactants.

7. Process for the production of dyestui intermediates whichscnmprises 'ciondensing1:?ai` oompound of the general formula: p 1,

(where Y represents a sulphur atom and R1, Rs and R1 are each lower alkyl groups) with a trithio ortho-formic lower-alkylester in the presence of a condensing agent selected from the class con-` sisting of hydrochloric acid and alkyl and aralkyl chlorides and in the presence of a solvent for the reactants. p l p 8. Process for the production of dyestui intermediates which comprises condensing a compound of the general "formula:

mediates which comprises'v fon'densngf iai. compound of the general formula;

(where Y represents a sulphur atom and R1,Ra and R4 are each lower alkyl groups) with an ortho-formic lower-alkyl ester in the presence of y methyl iodide anda solvent for the reactants.

12. Dyestui intermediates of the general formula:

` Y-.c=oH-CH= C-XR1 :c/ Y a `N- =o la where X and Y areeach selected from the class consisting of sulphur atoms and oxygen atoms, R1 is selected from the class consisting o-f the: hydrogen atom and hydrocarbon groups, and Rz and R3 are separate hydrocarbon groups.

13. Dyestuff intermediates of the general forjmula:

(where Y represents a sulphur atom and R1, R3

and R1 are each lower alkyl groups) with an ortho-formic lower-alkyl ester in the presence of a condensing agent selected from the class consisting of hydrochloric acid and alkyl and for the reactants. c 1

9. Process for the production of dyestui intermediates -Which comprises condensing a compound of the general formula: 1

(where Y represents a sulphur atom and R1, R3 and R4 are each lower alkyl groups) with a lower alkyl mercaptan in the presence of methyl iodide and a solvent for the reactants.

10. Process for the production of dyestui intermediates which comprises condensing a compound of the general formula:

(where Y represents a sulphur atom and R1, Ra and R4 are each lower alkyl groups) with a trithio ortho-formic lower-alkyl ester in the presence of methyl iodide and a solvent for the reactants.

. 11. Process for the production of dyestu interl aralkyl chlorides and in the presence of a solvent `where X'and Y are each selected from the class consisting of sulphur atoms and oxygen atoms, R1

1 is selected from the class consisting of the hydrogen atom and hydrocarbon groups, and R2 and Ra are lower-alkyl groups.

14. Dyestuffintermediates of the general formula:

where X and Y are each selected from the class y consisting `of sulphur atoms and oxygen atoms and R1, R2 and R3 are each lower a1ky1 groups.

15. Dyestuff intermediates of the general for- Where X and Y are each sulphur atoms and R1, Rz and R3 are each lower alkyl groups. 16.4 A compound of the formula:

which in the form of light crystals melts at 116 C. 

